Post-treatment Modification Using Deep Eutectic Solvent in PES and PES/SAPO-34 Membranes for Gas Separation

Mixed matrix membranes (MMM) are heavily studied and the main concern by researchers is the difficulty to obtain a high selectivity membrane with low defects, mainly interfacial voids due to the poor interaction between polymer matrix and filler. The functionalization of zeolite surface in PolyEtherSulphone (PES)/Silico-AluminoPhosphate-34 (SAPO-34) led to membranes with higher compatibility. Recently, the use of ionic liquids in the particles surface to improve the gas permeability and separation efficiency has presented advanced results. Although, the cost and environmental issues on Ionic Liquids (ILs) still represent a limit to its use. The Deep Eutectic Solvents (DESs) present an alternative route to replace ILs, with low-cost and environmentally friend. This paper aims to study the potential use of choline chloride/urea, a DES mixture, in ratio 1:2, to replace ILs as a post-healing methodology, showing a 20% increase in CO2 permeability in PES membranes and 15% increase in CO2/N2 selectivity in PES/SAPO-34 membranes due to an increase in compatibility between polymer and zeolite promoted by the post-treatment using DES.